Hydrocarbon refrigeration system with convection channel

ABSTRACT

A refrigeration system including a cabinet having an outer wall defining an insulated interior, an inner wall, and an insulative material disposed between the outer and inner walls. A cooling system is disposed in a space beneath the cabinet and cools the insulated interior. A convection channel is disposed between the outer and inner walls and extends and communicates air from an area outside an upper portion of the cabinet to the space beneath the cabinet. The channel is positioned within about 1.905 cm from the inner wall. The channel may have a plurality of different widths and may include a thermal bridge extending from the inner wall to the channel. The channel may include a primary branch extending from the upper portion of the cabinet to a junction point and a plurality of secondary branches extending from the junction point to a plurality of locations beneath the cabinet.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to refrigeration systems, particularlyrefrigeration systems that use hydrocarbon refrigerants and means forventing hydrocarbon refrigerant leaks.

2. Description of the Related Art

Refrigerators commonly include an insulated cabinet, the interior ofwhich is cooled by a cooling system. The cooling system is typicallydisposed within a housing, which is located beneath or behind thecabinet. The cooling system generally includes a compressor; a condenserfluidly connected to the compressor; and an evaporator fluidly connectedto both the compressor and the condenser and in thermal communicationwith the interior of the cabinet. In operation, a refrigerant gas entersthe compressor where it is compressed under high pressure. Thecompressed refrigerant gas then flows to the condenser where it iscooled in a series of coils and is condensed into a liquid. The liquidrefrigerant then flows to the evaporator where the liquid refrigerantabsorbs heat from the interior of the cabinet, thereby cooling theinterior and converting the refrigerant liquid back to a gas. Therefrigerant gas then flows back to the compressor where the cycle isrepeated. A fan is typically incorporated in the cooling system to coolthe compressor and force air through the condenser coils.

An effective refrigerant should be capable of readily evaporating at lowtemperatures and compressing at high pressure without decomposing.Consequently, compounds that are ideal for use as refrigerants arestable compounds having low evaporation temperatures. In the past, CFCs(chlorofluorocarbons) have been used as refrigerants. However, it isbelieved that CFCs are harmful to the environment and, as a result,hydrocarbon refrigerants, such as propane and isobutanes, have been usedin place of CFCs. Unfortunately, hydrocarbon refrigerants have a LowFlammability Limit, which means that even a small hydrocarbonrefrigerant leak in the housing could result in a build up ofhydrocarbon refrigerant to a concentration level above the LowFlammability Limit. A concentration of hydrocarbon refrigerant above theLow Flammability Limit is sufficient to trigger an explosion in thepresence of oxygen and a flame or spark.

If a hydrocarbon refrigerant leak occurs while the fan is running, thehydrocarbon refrigerant is, to some degree, flushed from the housing bythe fan. However, the fan typically does not run when the temperature inthe interior of the cabinet is within a specified range. If ahydrocarbon refrigerant leak occurs when the fan is off, the hydrocarbonrefrigerant concentration can accumulate in the housing to a levelexceeding the Low Flammability Limit, thereby creating favorablecombustion conditions.

Attempts have been made to prevent hydrocarbon refrigerant leaks byreducing the number of joints in the condenser, where leaks are mostlikely to occur. In addition, the operating pressure may be reduced inan effort to prevent hydrocarbon refrigerant leaks. Attempts have alsobeen made to develop systems for detecting hydrocarbon refrigerantleaks. Such systems may monitor the thermal dynamic parameters of thesystem and/or the electrical consumption of the compressor, or may sensethe molecules of hydrocarbon refrigerant in the air. Despite theseattempts, a need remains for a system that ventilates the cooling systemarea to effectively flush, dissipate and dilute hydrocarbon refrigerantleaks from the housing area.

SUMMARY OF THE INVENTION

The present invention provides a refrigeration system including acabinet having an outer wall, an inner wall defining an insulatedinterior, and an insulative material disposed between the outer andinner walls. A cooling system is disposed in a space beneath the cabinetand cools the insulated interior of the cabinet. A convection channel isdisposed between the outer and inner walls and extends from an areaoutside an upper portion of the cabinet to the space beneath thecabinet. The channel communicates air from the area outside the upperportion of the cabinet to the space beneath the cabinet to vent thecooling system.

The present invention also provides a refrigeration system including acabinet having an outer wall, an inner wall defining an insulatedinterior, and an insulative material disposed between the outer andinner walls; a cooling system disposed in a space outside a lowerportion of the cabinet for cooling the insulated interior of thecabinet; and a convection channel disposed between the outer and innerwalls. The channel is spaced apart from the inner wall and extends froman area outside an upper portion of the cabinet to the space outside thelower portion of the cabinet. The channel communicates air from the areaoutside the upper portion of the cabinet to the space outside the lowerportion the cabinet to vent the cooling system. The refrigeration systemalso includes at least one thermal bridge extending from the inner wallof the cabinet to the channel.

In addition, the present invention provides a refrigeration systemincluding a cabinet having an outer wall, an inner wall defining aninsulated interior, and an insulative material disposed between theouter and inner walls; a cooling system disposed in a space outside alower portion of the cabinet for cooling the insulated interior of thecabinet; and a convection channel disposed between the outer and innerwalls and extending from an area outside an upper portion of the cabinetto the space outside the lower portion of the cabinet. The channelincludes a plurality of widths, each of which decreases in size as thechannel extends from the upper portion of the cabinet to the lowerportion of the cabinet. The channel communicates air from the areaoutside the upper portion of the cabinet to the space outside the lowerportion the cabinet to vent the cooling system.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and objects of this invention,and the manner of attaining them, will become more apparent and theinvention itself will be better understood by reference to the followingdescription of embodiments of the invention taken in conjunction withthe accompanying drawings, wherein:

FIG. 1 is a front sectional view of a refrigeration system in accordancewith the present invention;

FIG. 2 is a side sectional view of a refrigeration system of FIG. 1taken along line 2-2 in FIG. 1;

FIG. 3 is a top perspective view of a cooling system in accordance withthe present invention;

FIG. 4 is a top perspective view of the housing of the cooling system ofFIG. 3;

FIGS. 5 and 6 are side sectional views of a prior art refrigerationsystem;

FIG. 7 is a front sectional view of another embodiment of therefrigeration system in accordance with the present invention;

FIG. 8 is a front sectional view of another embodiment of arefrigeration system in accordance with the present invention;

FIG. 9 is a front sectional view of another embodiment of arefrigeration system in accordance with the present invention;

FIG. 10 is a front sectional view of another embodiment of arefrigeration system in accordance with the present invention;

FIG. 11 is a side sectional view of another embodiment of arefrigeration system in accordance with the present invention;

FIG. 12 is a side sectional view of another embodiment of arefrigeration system in accordance with the present invention;

FIG. 13 is a top view of a cooling system according to one embodiment ofthe present invention;

FIG. 14 is a top view of a cooling system in accordance with anotherembodiment of the present invention;

FIG. 15 is a top view of a cooling system of a prior art refrigerationsystem;

FIG. 16 is a side sectional view of a prior art refrigeration system;and

FIG. 17 is a side sectional view of another embodiment of arefrigeration system in accordance with the present invention.

DETAILED DESCRIPTION

The embodiments hereinafter disclosed are not intended to be exhaustiveor limit the invention to the precise forms disclosed in the followingdescription. Rather the embodiments are chosen and described so thatothers skilled in the art may utilize its teachings.

Referring first to FIGS. 1 and 2, refrigeration system 10 according tothe present invention generally includes cooling system 30 and cabinet12. Cabinet 12 includes outer wall 14, inner wall 16 and insulativematerial 18 disposed between outer and inner walls 14 and 16. Inner wall16 defines insulated interior 20, which is cooled by cooling system 30.Cooling system 30 is located within housing 40, which is positionedbeneath cabinet 12. Cooling system 30 generally includes compressor 32;condenser 36, which is fluidly connected to compressor 32; evaporator34, which is fluidly connected to both compressor 32 and condenser 36and is in thermal communication with cabinet interior 20; and fan 38.

Referring now to FIGS. 3 and 4, compressor 32, condenser 36, evaporator34, and fan 38 are contained within housing 40. Housing 40 issubstantially rectangular and includes base 42, front wall 44, back 50,and pair of sidewalls 54, 56, all of which cooperate to define interiorspace 41. Front wall 44 includes first air inlet 46 through which airfrom outside housing 40 can enter space 41. Condenser 36 is positionedadjacent first air inlet 46 such that the cool ambient air drawn intospace 41 through first air inlet 46 flows over the coils of condenser36, thereby aiding in the cooling and condensing of the hydrocarbonrefrigerant contained within the coils. Back 50 includes first airoutlet 52 through which air can exit space 41. It should be understoodthat first air outlet 52 need not be a slot defined in a back wall asdepicted in FIGS. 3 and 4. Instead, back 50 can be open to the spaceoutside housing 40 such that nearly the entirety of back 50 can serve asfirst air outlet 52. In addition, first air inlets 46 need not behorizontal slots defined in front wall 44. Instead, first air inlets 46may be any shape, size, or design that will allow air to flow intohousing 40, for example, vertical slots.

As illustrated in FIGS. 5 and 6, refrigeration systems are commonlypositioned near a wall W of a building structure. Referring particularlyto FIG. 5, when fan 38 is running, air is drawn into space 41 throughair inlet 46 and is then forced out of space 41 and upward between wallW and outer wall 14 of cabinet 12, thereby dissipating any hydrocarbonrefrigerant that might have leaked into space 41. When fan 38 is notrunning, as illustrated in FIG. 6, the temperature of the air in space41 begins to rise due to the heat created by compressor 32. The warm air(represented by wavy arrows) then begins to rise between outer wall 14of cabinet 12 and wall W. However, the contrastingly cool ambient air(represented by straight arrows) located above cabinet 12 begins to sinkbetween wall W and outer wall 14. The sinking ambient air (straightarrows) counteracts the rising air (wavy arrows) from space 41, therebypreventing further upward movement of the air from space 41 and,ultimately, preventing the dissipation of any hydrocarbon refrigerantthat might have leaked into space 41.

Referring back to FIGS. 1 and 2, to vent space 41 and flush out anyhydrocarbon refrigerant, refrigeration system 10 includes convectionchannel 26. Convection channel 26 is disposed between outer wall 14 andinner wall 16 of cabinet 12 and extends from upper portion 22 of cabinet12 to lower portion 24 of cabinet 12. Channel 26 communicates with theair outside upper portion 22 of cabinet 12 by extending at one endthrough outer wall 14 at the top of cabinet 12. Channel 26 communicatesat its opposite end with space 41 within housing 40 by extending throughouter wall 14 at the bottom of cabinet 12. Channel 26 is positioned at adistance d from inner wall 16 and has a width or diameter D. Channel 26is cooled by transferring heat to nearby cooled interior 20 of cabinet12.

In operation, cool ambient air from outside upper portion 22 of cabinet12 sinks into channel 26 where it is further cooled by nearby interior20. As the air within channel 26 cools, its density increases. The densecool air in channel 26 overcomes the warm buoyant air from space 41,thereby forming a downward draft or flow through channel 26, asillustrated in FIG. 2.

To facilitate the cooling of the air within channel 26 and, thereby, thedownward draft of air through channel 26, channel 26 is positioned frominner wall 16 at distance d, which is no greater than that which wouldallow adequate cooling of channel 26. More particularly, positioningchannel 26 within about 1.905 centimeters (¾ inch) of inner wall 16achieves effective cooling of the air within channel 26 and sufficientdownward airflow. As shown in FIG. 8, channel 26 may be located directlyadjacent inner wall 16 such that the wall of channel 26 abuts the innerwall 16 of cabinet 12. This direct thermal contact between inner wall 16and channel 26 further facilitates the transfer of heat from channel 26to interior 20 and, ultimately, the cooling of the air within channel26.

To further facilitate the efficient and effective downward flow of airthrough channel 26, channel diameter D should be large enough to alloweffective downward flow, but not so large as to require an inefficientand unnecessarily large amount of heat transfer into interior 20.Channel diameters D falling between 0.3175 cm and 2.54 cm (⅛″ and 1″)achieves effective and efficient cooling and airflow. As shown in FIG.7, channel 26 may include multiple diameter portions, D₁, D₂. Channel 26includes an upper portion having diameter D₁ and a lower portion havingsmaller diameter D₂. The larger diameter D₁ of the upper portion ofchannel 26 insures sufficient cooling of the ambient air enteringchannel 26. The smaller diameter D₂ of the lower portion of channel 26reduces the amount of warm air that rises up from space 41 into channel26.

As shown in FIGS. 9 and 10, refrigeration system 10 may also include oneor more thermal bridges 28 extending from inner wall 16 of cabinet 12 tochannel 26. Thermal bridges 28 facilitate the heat transfer from channel26 to interior 20, thereby more effectively cooling the air withinchannel 26. As shown in FIG. 9, thermal bridges 28 can be comprised of aconductive material, such as aluminum, copper and/or steel.Alternatively, as shown in FIG. 10, thermal bridges 28 may comprise agap in insulative material 18 between channel 26 and inner wall 16.

Turning now to FIG. 1, channel 26 need not necessarily extend throughouter wall 14 at the top of cabinet 12, as shown in FIGS. 1-2 and 7-10.Instead, channel 26 can penetrate outer wall 14 at the upper side ofcabinet 12, as shown in FIG. 11. In this particular embodiment, channel26 includes an angled portion which is angled relative to the outer wall14. To avoid restricting air flow through channel 26, the angle θ of thechannel should be no greater than 75° with respect to the vertical.

Referring now to FIG. 12, channel 26 may also be branched to allow theventing of multiple locations in space 41. As shown in FIG. 12, channel26 includes primary branch 27, which extends from the top of cabinet 12to a junction point P; and two secondary branches 29A, 29B, which extendfrom junction point P to the bottom of cabinet 12. Secondary branches29A, 29B penetrate outer wall 14 at the bottom of cabinet 12 in twodifferent locations. Particularly, secondary branch 29A pierces outerwall 14 near front wall 44 just above condenser 36 to vent the condensercoils, while secondary branch 29B pierces outer wall 14 near back 50 tovent space 41 near evaporator 34. It should be understood that channel26 can include any number of secondary branches extending to a varietyof different locations in space 41. In addition, secondary branches 29A,29B can extend at any angle with respect to the vertical, provided thatthe angle does not restrict the flow of air. More particularly,secondary branch angles β measuring 75° or less with respect to thevertical achieve adequate airflow.

In another embodiment of the present invention illustrated in FIGS. 13and 14, fan 38 is positioned within housing 40 such that the axis A offan 38 is aligned along a vertical plane that defines anon-perpendicular angle α₁ relative a vertical plane P₁ alignedperpendicular to back 50 of housing 40. Referring particularly to FIG.13, fan 38 creates a first horizontal air flow f₁ in which air is drawninto housing 40 through first air inlet 46 and forced out of housing 40through first air outlet 52 in a direction non-perpendicular to back 50.Fan 38 directs the exiting first horizontal air flow f₁ in onehorizontal direction between wall W and back 50 of housing 40. Firsthorizontal airflow f₁ then mixes with ambient air, thereby diluting anddissipating any hydrocarbon refrigerant.

First horizontal air flow f₁, in turn, engages the air outside housing40 and induces a second horizontal air flow f₂ in a directionsubstantially parallel to the diagonal X of base 42. In other words,second horizontal air flow f₂ flows about housing 40 in a direction thatis non-perpendicular to housing 40. The non-perpendicular direction ofsecond horizontal air flow f₂ causes air flows f₁ and f₂ to meet and mixin a mixing region, which is represented by the encircled area in FIG.13. This mixing of first and second horizontal air flows f₁ and f₂further dilutes and dissipates any hydrocarbon refrigerant in firsthorizontal air flow f₁ to more effectively dilute the hydrocarbonrefrigerant and maintain the hydrocarbon refrigerant concentration at alevel below the Low Flammability Limit.

Referring now to FIG. 15, in prior refrigeration systems fan 38 a ispositioned with its axis A perpendicular to back 50 a. In thisconfiguration, fan 38 a creates air flow f_(1a) in which air is drawninto housing 40 a through air inlet 46 a and forced out through outlet52 a in a direction perpendicular to back 50 a. The exiting air flow isdeflected by wall W in both horizontal direction. Generally, first airflow f_(1a) does not induce a substantial second air flow f_(2a).However, the second air flow f_(2a) that is induced does not flow in thedirection of the housing diagonal. Instead, second air flow f_(2a)encounters front wall 44 a and is deflected in a direction parallel towall 44 a. Consequently, first and second air flows do not meet and donot further mix in a mixing region.

Referring back to FIG. 13, angle α₁ of fan 38 can be any angle that isnon-perpendicular to back 50. However, favorable air flow results areachieved when fan 38 is positioned such that non-perpendicular angle α₁is between about 5° and 75° relative to a vertical plane P₁ alignedperpendicular to the back 50 of housing 40.

Referring now to FIGS. 3, 4 and 14, refrigeration system 10 may includepartition 60 which extends from front wall 44 to side wall 54 to createcompressor enclosure 62. Compressor 32 may then be positioned withincompressor enclosure 62 to shield the compressor, which includeselectrical components having the potential of producing a spark, fromthe condenser, which is the component from which hydrocarbon refrigerantleaks most likely occur. In this arrangement the potential forcombustion is reduced by physically separating the spark source from theleak source. Still referring to FIGS. 3, 4 and 14, housing 40 may alsoinclude a second air inlet 48 defined in front wall 44 and second airoutlet 58 defined in side wall 54. Both second air inlet 48 and secondair outlet 58 are in communication with the interior of compressorenclosure 62 to vent compressor 32. As noted above, second horizontalair flow f₂ flows about housing 40 in a direction non-perpendicular tohousing 40. Second horizontal airflow f₂ induces a third horizontalairflow f₃, which enters compressor enclosure 62 through second airinlet 48 and exits compressor enclosure 62 through second air outlet 58,thereby cooling compressor 32.

Referring now to FIG. 16, in prior systems fan 38 a is positioned suchthat a horizontal plane aligned along axis A defines a perpendicularangle relative to back 50 a. In this configuration air flows intohousing 40 a through air inlets 46 a and exits housing 40 a through airoutlets 52 a. The air exiting housing 40 a flows in a directionperpendicular to back 50 a such that when the air meets the wall W it isdeflected in both the upward and downward directions. The air flowing inthe downward direction then flows under housing 40 a. When the air exitsthe area beneath housing 40 a, the air can be drawn back into housing 40a through air inlet 46 a. Consequently, the air flowing downward neverleaves the area beneath cabinet 12 a and can be re-circulated back intospace 41 a of housing 40. This may ultimately result in a hydrocarbonrefrigerant accumulation to a level above the Low Flammability Level.

Referring now to FIG. 17, according to the present invention, fan 38 mayalso be inclined, as shown in FIG. 17. More specifically, fan 38 may bepositioned such that a horizontal plane aligned along axis A defines asecond non-perpendicular angle α₂ relative to a horizontal plane P₂aligned perpendicular to back 50 of housing 40. In this embodiment fan38 induces a vertical air flow f₄ in which air exiting first air outlet52 is directed upward, thereby preventing the flow of air beneathhousing 40 and preventing the re-circulation of air into housing 40.Angle α₂ can be any angle non-perpendicular to horizontal plane P₂.However, favorable vertical air flow results are achieved when fan 38 ispositioned such that a horizontal plane aligned along the axis A definesa non-perpendicular angle α₂ of between about 15° and 65° relative tohorizontal plane P₂, which is aligned perpendicular to back 50 ofhousing 40.

While this invention has been described as having an exemplary design,the present invention may be further modified within the spirit andscope of this disclosure. This application is therefore intended tocover any variations, uses, or adaptations of the invention using itsgeneral principles. Further, this application is intended to cover suchdepartures from the present disclosure as come within known or customarypractice in the art to which this invention pertains.

1. A refrigeration system comprising: a cabinet having an outer wall, aninner wall and an insulative material disposed between said outer andinner walls, said inner wall defining an insulated interior; a coolingsystem for cooling said insulated interior of said cabinet, said coolingsystem disposed in a space beneath said cabinet; and a convectionchannel disposed between said outer and inner walls and extending froman area outside an upper portion of said cabinet to said space beneathsaid cabinet, said channel communicating air from said area outside saidupper portion of said cabinet to said space beneath said cabinet to ventsaid cooling system.
 2. The refrigeration system of claim 1 furthercomprising at least one thermal bridge extending from said inner wall ofsaid cabinet to said channel.
 3. The refrigeration system of claim 2wherein said at least one thermal bridge is comprised of a conductivematerial.
 4. The refrigeration system of claim 2 wherein said insulativematerial is disposed between said inner wall and said channel; and saidat least one thermal bridge is comprised of a gap in said insulativematerial.
 5. The refrigeration system of claim 1 wherein said channel ispositioned within a distance of about 1.905 cm from said inner wall. 6.The refrigeration system of claim 5 wherein said channel is positioneddirectly adjacent said inner wall.
 7. The refrigeration system of claim1 wherein said channel has a plurality a different widths.
 8. Therefrigeration system of claim 1 wherein a portion of said channelextends at an angle with respect to said outer wall.
 9. Therefrigeration system of claim 8 wherein said angle is less than about75°.
 10. The refrigeration system of claim 1 wherein said channel isbranched, said branched channel comprising a primary branch extendingfrom said area outside said upper portion of said cabinet to a junctionpoint; and a plurality of secondary branches extending from saidjunction point to a plurality of locations in said space beneath saidcabinet to vent said plurality of locations.
 11. A refrigeration systemcomprising: a cabinet having an outer wall, an inner wall and aninsulative material disposed between said outer and inner walls, saidinner wall defining an insulated interior; a cooling system for coolingsaid insulated interior of said cabinet, said cooling system disposed ina space outside a lower portion of said cabinet; a convection channeldisposed between said outer and inner walls, said channel spaced apartfrom said inner wall and extending from an area outside an upper portionof said cabinet to said space outside said lower portion of saidcabinet, said channel communicating air from said area outside saidupper portion of said cabinet to said space outside said lower portionsaid cabinet to vent said cooling system; and at least one thermalbridge extending from said inner wall of said cabinet to said channel.12. The refrigeration system of claim 111 wherein said at least onethermal bridge is comprised of a conductive material.
 13. Therefrigeration system of claim 11 wherein said insulative material isdisposed between said inner wall and said channel; and said at least onethermal bridge is comprised of a gap in said insulative material. 14.The refrigeration system of claim 11 wherein said channel is positionedwithin a distance of about 1.905 cm from said inner wall.
 15. Therefrigeration system of claim 11 wherein a portion of said channelextends at an angle with respect to said outer wall.
 16. Therefrigeration system of claim 11 wherein said angle is less than about75°.
 17. The refrigeration system of claim 11 wherein said channel isbranched, said branched channel comprising a primary branch extendingfrom said area outside said upper portion of said cabinet to a junctionpoint; and a plurality of secondary branches extending from saidjunction point to a plurality of locations in said space outside saidlower portion of said cabinet to vent said plurality of locations.
 18. Arefrigeration system comprising: a cabinet having an outer wall, aninner wall and an insulative material disposed between said outer andinner walls, said inner wall defining an insulated interior; a coolingsystem for cooling said insulated interior of said cabinet, said coolingsystem disposed in a space outside a lower portion of said cabinet; anda convection channel disposed between said outer and inner walls andextending from an area outside an upper portion of said cabinet to saidspace outside said lower portion of said cabinet, said channel having aplurality of widths, said plurality of widths decreasing in size as saidchannel extends from said upper portion of said cabinet to said lowerportion of said cabinet, said channel communicating air from said areaoutside said upper portion of said cabinet to said space outside saidlower portion said cabinet to vent said cooling system.
 19. Therefrigeration system of claim 1 wherein said channel is spaced apartfrom said inner wall and said channel is positioned within a distance ofabout 1.875 cm from said inner wall.
 20. The refrigeration system ofclaim 19 further comprising at least one thermal bridge extending fromsaid inner wall of said cabinet to said channel.
 21. The refrigerationsystem of claim 20 wherein said at least one thermal bridge is comprisedof a conductive material.
 22. The refrigeration system of claim 20wherein said insulative material is disposed between said inner wall andsaid channel; and said at least one thermal bridge is comprised of a gapin said insulative material.
 23. The refrigeration system of claim 18wherein said channel is positioned directly adjacent said inner wall.24. The refrigeration system of claim 18 wherein a portion of saidchannel extends at an angle of between about 7° and 75° with respect tosaid outer wall.
 25. The refrigeration system of claim 18 wherein saidchannel is branched, said branched channel comprising a primary branchextending from said area outside said upper portion of said cabinet to ajunction point; and a plurality of secondary branches extending fromsaid junction point to a plurality of locations in said space outsidesaid lower portion of said cabinet to vent said plurality of locations.